As someone who is extremely low carb (average less than 5g/day), I can say that they are not required for energy. My energy levels are far more consistent throughout the day than they were when consuming more carbs.

The carbs I do consume are mainly the lactose in dairy products, dextrose in cured meats, and the occasional treat - like a handful of raisins, or a bite or two of cheesecake. I actually try to consume any *treats* at night, so I don't inadvertently end up in an energy fluxuation pattern. Carbs in the morning are horrible.